A hidden piece of Sydney history has been uncovered as part of construction work at Wynyard Station.

Long-lost stairs which were walled off more than 50 years ago have been revealed during the current upgrade to the railway station. But they will soon be gone again – this time for good – to make more room on the passenger concourse.

Some parts of the stairs, which may be visible to the public through barriers until they are removed, will be salvaged for restoration purposes.

From 1932, the stairs serviced platforms 1 and 2 at the station. But as commuters know, only platforms 3, 4, 5 and 6 are now in use at Wynyard.

So what happened to platforms 1 and 2?

According to the NSW Office of Environment and Heritage, before the Sydney Harbour Bridge was built, a north-east rail connection was planned that would run from Wynyard towards Mosman and the northern beaches.

The bridge was originally designed to carry four train lines – two on the west side and two on the east – but this proposal was abandoned. Instead, the north shore tram service was extended across the bridge to Wynyard – the last of the main Sydney tram lines built.

The Wynyard tramway and station operated from 1932 and were the only underground components of the Sydney tram network, which was once among the world’s biggest.

The tramway that once crossed the Sydney Harbour Bridge to Wynyard Station. Photo: Supplied

The tram station was on the upper level of Wynyard Station using platforms 1 and 2, adjacent to the railway platforms 3 and 4, and accessed through a separate concourse entrance – via the long-lost stairs.

Buses started to replace trams in 1933. In the 1950s, the tram service was discontinued across Sydney and on June 29, 1958, the city’s last tram ran out of Wynyard.

When the trams stopped, the stairs from the concourse to the tram platforms were sealed off and have stayed hidden – until now.

Around 1964, the former tram tunnels and station were converted for use as a carpark for the Menzies Hotel and as public parking. One of the tunnels was converted for use as a storage facility after reportedly being used by the police as a pistol firing range.

Repairs are carried out on a tram at Wynyard Station in April 1956. Photo: Fairfax Media

A Transport for NSW spokeswoman said the stairs would be removed to create more space on the concourse – a decision approved within the Wynyard Station Upgrade Review of Environmental Factors.

“Elements from these stairs such as original balustrades and hand rails will be salvaged and used to restore existing stairs on the concourse,” she said.

As a result of the upgrades that have occurred since the station opened in 1932, little “original fabric” remains within Wynyard Station and Transport House, the building above the station that was the original headquarters of NSW State Railways.

“However, there is the potential for unexpected finds,” the spokeswoman said.

In the event of a historical discovery, archival recording would be undertaken and measures implemented as part of a Heritage Construction Environmental Management Plan.